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3 years ago

22)

Chemistry

1 answer:

Setler79 [48]3 years ago

6 0

Answer: A) 4.2 x 10^20

Explanation:

All of the answers are pretty much the same so it comes down to significant digits.

You always go with the least number of significant digits that you have been given.

So 0.24g only has 2 so our answer will only have 2 significant digits.

If you want to know how to do the math here it is:

Avogadro's Number: 6.022 x 10^23

This number also equals 1 mole.

1 mole of sucrose is equal to 342.3g.

So the equation is set up like this:

0.24g x 1 mol / 342.3 g x 6.022 x 10^23 / 1 mol = 4.2 x 10^20 molecules.

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Which balance is a centigram balance? A Or B

MaRussiya [10]

I think it is B because you didn’t type the options

5 0

3 years ago

At 25°C and constant pressure, carbon monoxide gas combines with oxygen gas to give carbon dioxide gas with the evolution of 10.

stealth61 [152]

Answer : The value of $\Delta H$ for the reaction is, -565.6 kJ

Explanation :

First we have to calculate the molar mass of CO.

Molar mass CO = Atomic mass of C + Atomic mass of O = 12 + 16 = 28 g/mole

Now we have to calculate the moles of CO.

$\text{Moles of }CO=\frac{\text{Mass of }CO}{\text{Molar mass of }CO}=\frac{1g}{28g/mole}=\frac{1}{28}mole$

Now we have to calculate the value of $\Delta H$ for the reaction.

The balanced equation will be,

$2CO(g)+O_2(g)\rightarrow 2CO_2(g)$

From the balanced chemical reaction we conclude that,

As, $\frac{1}{28}mole$ of CO release heat = 10.1 kJ

So, 2 mole of CO release heat = $2\times 28\times 10.1=565.6kJ$

Therefore, the value of $\Delta H$ for the reaction is, -565.6 kJ (The negative sign indicates the amount of energy is released)

4 0

3 years ago

A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4

Harman [31]

Na₃PO₄ -----> 3Na(+) + PO₄(3-)
y-y.......................3y...........y

3y = 1.2
y = 0,4M

Na₃PO₄ -----> 3Na(+) + PO₄(3-)
0,4-0,4..............1,2..........0,4
0.........................1,2..........0,4

C = n/V
n = C×V
n = 0,4×0,65L
n = 0,26 mol Na₃PO₄

mNa₃PO₄: (23×3)+31+(16×4) = 164 g/mol

164g ----- 1 mol
Xg -------- 0,26 mol
X = 164×0,26
X = 42,64g Na₂SO₄

5 0

3 years ago

The atomic number is the same as the number of ________.

Zanzabum

Answer:

number of electrons

Explanation:

(happy to help)

5 0

3 years ago

ANSWER ASAP PLEASE

user100 [1]

Density is equal to mass divided by volume so the densest object will be the object that has the largest mass in the smallest area. In this case object A is the densest with a density of 10g/cm^3. I hope this helps. Let me know if anything is unclear.

3 0

3 years ago